MainWindow.xaml

<Window x:Class="WPFWebView2TabControl.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WPFWebView2TabControl"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Window.DataContext>
        <local:MainWindowViewModel />
    </Window.DataContext>
    <Window.Resources>
        <DataTemplate x:Key="TabBrowserDataTemplate"
                      DataType="{x:Type local:BrowserTabItemViewModel}">
            <Grid>
                <local:BrowserTabItemUC />
            </Grid>
        </DataTemplate>
        <DataTemplate x:Key="TabBrowserHeaderDataTemplate">
            <Grid>
                <StackPanel Orientation="Horizontal">
                    <TextBlock Text="{Binding Title}"
                               TextTrimming="CharacterEllipsis"
                               MaxWidth="140"
                               VerticalAlignment="Center" />
                    <Border BorderThickness="4" />
                    <Button x:Name="CloseTabButton"
                            Content="X"
                            Padding="0,-3,0,0"
                            Background="Transparent"
                            Command="{Binding DataContext.TabCloseCommand,
                              RelativeSource={RelativeSource AncestorType={x:Type TabControl}}}"
                            CommandParameter="{Binding}"
                            VerticalAlignment="Top"
                            HorizontalAlignment="Right"
                            Height="14"
                            Width="14" />
                </StackPanel>
                <Grid.ToolTip>
                    <ToolTip Placement="Top">
                        <StackPanel Orientation="Vertical">
                            <TextBlock Text="{Binding Title}"
                                       MaxWidth="300"
                                       TextWrapping="Wrap"
                                       FontWeight="Black" />
                            <TextBlock Text="{Binding BaseURL}" />
                        </StackPanel>
                    </ToolTip>
                </Grid.ToolTip>
            </Grid>
            <DataTemplate.Triggers>
                <MultiDataTrigger>
                    <MultiDataTrigger.Conditions>
                        <Condition Binding="{Binding RelativeSource={RelativeSource TemplatedParent},Path=IsMouseOver}"
                                   Value="True" />
                    </MultiDataTrigger.Conditions>
                    <Setter TargetName="CloseTabButton"
                            Property="Opacity"
                            Value="1" />
                </MultiDataTrigger>
                <MultiDataTrigger>
                    <MultiDataTrigger.Conditions>
                        <Condition Binding="{Binding RelativeSource={RelativeSource TemplatedParent},Path=IsMouseOver}"
                                   Value="False" />
                    </MultiDataTrigger.Conditions>
                    <Setter TargetName="CloseTabButton"
                            Property="Opacity"
                            Value="0" />
                </MultiDataTrigger>
            </DataTemplate.Triggers>
        </DataTemplate>
    </Window.Resources>
    <Grid>
        <TabControl x:Name="BrowserTabControl"
                    SelectedIndex="{Binding BrowserTabControlSelectedIndex, Mode=TwoWay}"
                    ItemsSource="{Binding TabCollection}"                    
                    ItemTemplate="{StaticResource TabBrowserHeaderDataTemplate}"
                    ContentTemplate="{StaticResource TabBrowserDataTemplate}"/>
    </Grid>
</Window>